Need some help! The rats have discovered my feeder so I have been taking them out with a Avanti 853 (.17). I like the gun, it is quiet and accurate. The problem is unless I make a head or spine shot the rat runs a short distance to the bushes and gets away. Now to my question, I am looking at a Stingray in either .22(720fps) or .25(620fps) in hopes of anchoring a rat on the spot. Which one do you guys think would serve my purpose. Also would one be louder than the other. Thanks in advance.